Measuring instrument.



S. M. JOINER.

MEASURING INSTRUMENT.

APPLICATION FILED DEC. 19, 1912.

1,181,388. Patented May 2, 1916.

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S. M. JOINER.

MEASURING INSTRUMENT.

APPLICATION FILED DEC. 19 I912.

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M/KM SEW is 3 a q WW W6 SEABORN M. J OINER, OF PORTERSVILLE, CALIFORNIA.

MEASURING INSTRUMENT.

Specification of Letters Patent.

Patented May 2, 1916.

Application filed December 19, 1912. Serial No. 737,703.

To all whom it may concern Be it known that I, SnABonN M. JOINER, acitizen of the United States, residing at Portersville, in the county ofTulare and State of California, have invented certain new and usefulImprovements in Measuring Instruments; and I do declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

This invention relates to improvements in measuring instruments and moreparticu larly to instruments designed for angle trisection. I

The object of the invention is to provide a simple and reliableinstrument for bisecting and tri-secting angles Without any calculatingbeing necessary.

With this and other objects in view, the invention consists of certainnovel features of construction, and the combination and arrangement ofparts as will be more fully described and claimed.

In the accompanying drawings: Figure 1 represents a plan view ofa'measuring instrument constructed in accordance with this inventionshown in full lines in one position and in dotted lines in anotherposition; Fig. 2 is a longitudinal section taken on the line 22 of Fig.1; Fig. 3 is a transverse section taken on the line 33 of Fig. 1; Fig. 1is a similar view taken on the line 41 of Fig. 1. Fig. 5 shows a diagramillustrating the manner in which this instrument is constructed; Fig. (3is a similar view showing the instrument in partially collapsedposition.

In the embodiment illustrated, a frame 1 is shown composed of two bars 2and 3 pivotally connected at one end by a rivet 6 and to longer bars atand 5 pivotally connected at one end to the free ends of the firstmentioned bars by rivets 7 and having their free ends crossed one uponthe other and pivotally connected by-a rivet 8 at points spaced from thepivot 7 a distance corresponding to the length of saidarms or bars 2'and3 to provide a frame, the four side members of which are of the samelength. The crossed ends of the bars 4 and 5 project the same distancebeyond the rivet 8 and are designed as handles to assist in manipulatingthe device.

A longitudinally slotted angle bisecting bar 9 is slidably mounted onthe rivets 6 and 8, slots 10 and 11 being provided for this purpose,said slots extending throughout the greater portion of the length ofsaid bar and being spaced apart at their inner ends by a solid portion 9which strengthens the bar and prevents spreading of the side walls ofthe slots thereof. The rivets 6 and 8 are sufficiently loose to permitthe bar 9 to slide freely thereon and the side bars of the frame toswing freely to permit opening and closing of the frame to adapt it foruse in measuring or dividing different angles.

Two trisecting bars 12 and 13 have one end pivotally mounted on thepivot 6 and their other ends are longitudinally slotted for aboutone-third of the length thereof, the inner portions of said slots forabout one-fourth of their length being straight as shown at let and theremaining threefourths thereof curved as shown at 15 to adapt the bars2, 3, 12 and 13 to maintain an equidistant relation to each other duringthe opening'and closing of the instrument for accurately trisecting anangle. Thumb nuts 16 engage screws 16 which extend through the slots ofthe bars 12 and 13 and engage apertures in the bars 4- and 5, theposition of said apertures being determined by means to be described.

In constructing this instrument, the four bars 2, 3, 4 and 5 of theframe 1 having been connected as above described, the connecting pointof the bars 12 and 13 with the frame bars 4 and 5 is determined bydrawing an arc line A of 90, of which the pivot (3 represents thecenter. This arc line is graduated into degrees with the pivots 7disposed at the ends thereof as shown in Fig. 5. The two bars shown at12 and 13 which are pivotally connected at 6 with each other and withthe connected ends of the bars 2 and 3, cross this are line at 30 fromthe ends of said 'line and from each other and the points where saidbars 12 and 13 cross said line divide it into thirds and cause said bars12 and 13 to cross bars 4i and 5 at the points indicated by the setscrews 16 at which points the apertures to receive said set screws areformed in said bars 4 and 5. By exper1- ment it was found that thesebars 12 and 13 would not properly trisect an angle when the slotstherein were straight throughout their length and to enable them toaccurately trisect an angle when mounted as above set forth, it wasfound necessary that these slots be curved throughout aboutthree-fourths of their length toward their free ends and that the radiusof the curve C on which the slotted portions 15 are formed should beequal to a chord or straight line drawn from the center of one of thepivots 7 to the point 9 where the arc line A intersects the longitudinal axis of bar 9. Then using the point 9" where the arc line Acrosses the longitudinal axis of the bisecting bar 9 as a center, andthe radius obtained as above described, an are 0 was struck through oneof the pivots 7. The line L parallel with one of the bars 12 or 13 andspaced from the inner edge thereof a distance equal to the radius of thecurve 0 was then drawn, (see Fig. 5). Then using screw 16 as a center,an arc line L was struck through the line L, the radius used being thesame as that used for are 0 and the point of intersection of said linesL and L as shown at L formed the center of the curve C on which the slot15 of bar 12 was formed, the radius of this curve C corresponding to theradius of the curve 0.

In the operation of this instrument, the nuts 16 are loosened and thebars 2 and 3 are placed with their longitudinal axes on the linesforming the angle to be measured and the bars 9, 12 and 13 wouldautomatically adjust themselves during the arrangement of the bars 2 and3 to divide said angle bar 9 bisecting it and the bars 12 and 13trisecting it. The nuts 16 are then tightened to hold the parts of theinstrument in ad justed position and the bars 2, 3, 12 and 13 betweenthe pivots 6, 7 and 8 will correspond to the angle measured. The bars 2,3, 4 and 5 being pivotally connected and the bisecting and trisectingbars also pivotally'connected, it will be obvious that the instrumentmay be contracted and expanded to fit the angles of any desired size,and that the bars 12 and 13 will automatically trisect the angle and thebar 9 will bisect it. The bar 9 is slotted to provide for itslongitudinal adjustment to adapt the bisecting line to be drawn of anydesired length.

I claim as my invention:

1. An angle measuring instrument comprising a quadrilateral frame, themembers of which are pivotally connected one to another, angle dividingmeans comprising two bars pivotally mounted on one of the pivots of saidframe and diverging with their free ends slidably and pivotallyconnected with two of the side members of the frame, and

means for holding said dividing means in adjusted position.

2. An angle measuring instrument comprising a frame, the members ofwhich are pivotally connected one to another, the length of the membersbetween said pivots being equal, angle dividing bars pivotally mountedat one end on one of the pivots of the frame and slotted longitudinally,and set screws extending through said slots and engaging two of themembers of said frame.

3. An angle measuring instrument comprising a frame, the members ofwhich are pivotally connected one to another, the length of the membersbetween said pivots being equal, angle dividing bars pivotally mountedat one end on one of the pivots of the frame and slotted longitudinallyat their free ends for about one-third of their length, said slots beingstraight approximately onefourth of their length at their inner portionsand the remainder curved inwardly, and set screws extending through saidslots and engaging two of the members of said frame at points spacedfrom the pivotal connection of said members.

4:. An angle measuring instrument comprising an equilateralquadrilateral frame, the side bars of which are pivotally connected,angle trisecting bars pivotally mounted at one end on one of the framepivots, said bars being slotted longitudinally, and set screws extendingthrough said slots and engaging two of the side bars of said frame.

5. An angle measuring instrument comprising an equilateral quadrilateralframe, the side bars of which are pivotally connected, angle trisectingbars pivotally mounted at one end on one of the frame pivots, said barsbeing slotted longitudinally at their free ends, set screws extendingthrough said slots and engaging two of the side bars of said frame, andan angle bisecting bar slotted longitudinally and slidably engaged withdiagonally opposite frame pivots, said bisecting bar extending betweensaid trisecting bars.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

SEABORN M. J OINER.

Witnesses:

C. C. SAMSWOBTH, Jr., HUGH TEMPLETON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of mum, Washington, D. C.

